1. CATALYST OBJECTIVES DATE: 02/10/2015
Describe the 3 types of plate boundaries.
Explain how convection currents move plates.
Describe 1 type of plate movement.

2. Plate Tectonics
Earth’s crust is divided into 12 major plates (tectonic plates) which are moving in various directions.
Plate Boundary
Where 2 plates meet

3. Plate Tectonics

4. Types of Plates Continental Crust Oceanic Crust Thick (10 - 70 km)
Less Dense
Mostly very old
Thin (~7 km)
More Dense
Young age of rocks

5. Convergent Boundaries
Plate Boundaries
Divergent Boundaries
Convergent Boundaries
Oceanic-Oceanic
Oceanic-Continental
Continental-Continental
Transform Boundaries

6. 1. Divergent Boundaries 2 or more plates separate or pull apart
Magma rises between the plates and makes new rocks
Formation of ridges (in the ocean) and rift valleys (on the continents)

7. 1. Divergent Boundaries

8. 1. Divergent Boundaries

9. 1. Divergent Boundaries

10. 2. Convergent Boundaries
2 or more plates moving towards each other
3 types
Oceanic-Oceanic
Oceanic-Continental
Continental-Continental

11. What will happen to the oceanic plate when it sinks?
2a. Oceanic-Oceanic
Collision of 2 oceanic crusts
One oceanic crust will eventually slide under the other
What will happen to the oceanic plate when it sinks?

12. 2a. Oceanic-Oceanic
Subduction
When a more dense plate goes under (subducts) a less dense plate

13. 2a. Oceanic-Oceanic

14. Trenches and Island Volcanoes form at this boundaries
2a. Oceanic-Oceanic
Trenches and Island Volcanoes form at this boundaries

15. 2b. Oceanic-Continental
Collision between an oceanic plate and a continental plate
Oceanic crust is more dense than continental crust so…
Oceanic crust sinks below continental crust

16. 2b. Oceanic-Continental
What will happen to the oceanic plate when it sinks?
SUBDUCTION
Oceanic

17. 2b. Oceanic-Continental
Trenches and Land Volcanoes form at these boundaries

18. Plate Tectonics

19. 2c. Continental-Continental
Collision of 2 continental plates
Similar density, so neither subducts
Formation of mountains

20. 2c. Continental-Continental
Example: Indian-Australian Plate vs. Eurasian Plate
Collision formed Himalaya Mountains

21. 2c. Continental-Continental

23. 3. Transform Boundaries
2 plates slide horizontally past each other
Forms long lines in the Earth (faults) and deformation of the land

24. 3. Transform Boundaries

25. 3. Transform Boundaries
Example: San Andreas Fault, CA

26. 3. Transform Boundaries

27. But what is causing these plates to move?
Convection Currents!